The International Space Stations future lifeboat took to the air again Friday in a test of its slightly new shape, avionics and aerodynamic control surfaces.

Carried by a B 52 bomber, X 38 #131-R, spent about two hours at 45,000 feet (13,500 meters) as engineers ran through tests above NASAs Dryden Flight Research Center in California.

Another goal of the vehicles flight was to "cold soak" the vehicle at high altitude as an initial test of the seven-seat crafts ability to fly at high altitude.

The X 38, also referred to as the Crew Return Vehicle, will spend the next two years in flight tests. In 2002, an X 38 being built at Johnson Space Center will go aloft inside a space shuttle and return to Earth on its own. The space agency will award a contract this fall to build four of the vehicles.